1. Field of the Invention
The invention relates to the field of water purification devices, and in particular to a low-cost, small scale purification.
2. Description of Related Art
Access to clean water is an essential human necessity. In developing countries, in emergency situations, and simply for outdoor activities, there is a need for simple, lightweight, and cheap water purification devices. Numerous filtering devices, e.g. using ceramic filters, multiple water collecting devices with intervening filters etc. are known.
U.S. Pat. No. 4,879,030 describes a water purification and emergency nutrition package. The package comprises a compartment having a semipermeable membrane which allows it to desalinate water, and a compartment comprising a mixture of water-soluble nutrients such as fructose. Once a minimum amount of water has entered the package, osmotic pressure caused by the water-soluble nutrients drives the further transfer of water through the semipermeable membrane. Applicability of the device is limited in that it can be used only once, in that it does not provide water alone, but rather a mixture of water and sugars, i.e. nourishment, and in that it is focused on the desalination of sea water.
US 2002/008062 A1 discloses a water purifier comprising a cylindrical body and a piston sliding inside the cylinder. The piston can be manually withdrawn, sucking water through a filter and into the device. Pushing the piston back causes the water to be expelled through the same filter.